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What's behind the Vaut mayhem?
Page 26
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YOUR RECENT coverage of the teething troubles marring the introduction of the Maut autobahn tolling scheme makes no mention of another cause of the hold-up: German authorities wanted to include toll rate concessions for Euro-4 trucks.
The aim was to persuade buyers of new trucks to specify voluntarily (at considerable extra cost) the urea-fed SCR deN0x packages now ostensibly available from Mercedes. MAN and others. SCR would enable Euro-4 emission limits to be met early — ahead of the October 2006 EU deadline for all new vehicles — with politically attractive environmental benefits.
But problems have arisen with enforcement. It was realised very late in the day that though SCR might be installed, there would be no OBD (on-board diagnostic) system available for the planned Maut scheme start-up date.That was necessary to check there was urea solution of the required AdBlue specification strength — rather than just water, for example — in the tank, with a read-out accessible to the law enforcers.
Manufacturing schedules for the production of OBD hardware to monitor the level of liquid in the urea tank and its aqueous solution strength [measured by passing an electric current through the liquid] have been geared to the Euro-4 deadline.
Those equipment manufacturers are in any case diffident about the commercial rewards, because they are expecting the legislators to demand (as soon as they become available in four or five years' time) more sophisticated exhaust tailpipe sensors able to provide a direct electronic readout of NOx emissions.
Alan Bunting Hertfordshire